Calculating length based on bpm?

[ghost ghost ghost]

Weird question....how would I go about figuring out the length (in seconds) of say, 4 bars of a 80bpm track, or 1 bar of a 100bpm track...or whatever, is there any way to calculate this? I'm not a technically minded person and I know nothing about music theory at all, let alone the maths of it all. I know how to operate my two samplers, I know whether something sounds dope or not to my ears, and up until now that's all I thought I needed to know, guess I was wrong. I've searched the internet on and off pretty much all evening but I'm just getting more confused every time I come up with some information.

Can anyone help? Thanks

[tape smoke]

bpm is beats per minute .
i dont know the formula exactly, but it would be easy enough with some basic math skills ( which i dont have )

60 bpm 2 bars is 8 seconds.
1.5 second difference between 60 and 70
70 bpm 2 bars is 6.85 seconds
.85 second difference between 70 and 80
80 bpm 2 bars is 6 seconds
.67
90 bpm 2 bars is 5.33 seconds .


so looking at that is appears the time in seconds versus the bpm accelerates as it goes up, i know my math is really funny and it never gets me anywhere because i dont know algebra but maybe this can be a foundation for somewho does.

sorry for my hill billy education

[ghost ghost ghost]

I think I figured out how to find the time difference between two.

Thanks a lot

[tape smoke]

i think its interesting, because to pitch a sample an octave makes it play twice as fast. which is cool for bass sometimes, make a copy of the sample and pitch it down an octave. and play it with the original and filter it, its dope. up is cool to for speeding up drums double.

[metronome]

the formula is the following: 60 / bpm = one bar in seconds.

there's also a transposition formula: {sample length} * (n / 120)^2
where 'n' is transposition units in cents, logarithmic units of pitch. one half-tone equals 10 cents. so if you want to transpose your sample one half-tone up, the formula is {sample length} * (10/120)^2; if you want to make it one tone lower, it's {sample length} * (-20/120)^2. i don't know if '^2' is a common way of writing square root.

hope this helps.

[dollarllama d]

shit yall got it to a science. lol

[cartesia]

60 divided by BPM = how many seconds 1 beat takes.

so say

75BPM

60 divided by 75 = 0.8

so 1 beat at 75BPM is 0.8seconds.

for 1 bar just multiply 4 by 0.8 or whatever the result of the first equation is... for more than 1 bar.. well pretty obvious

[tape smoke]

so if 1 beat at 60 bpm is .8 seconds ,

then 2 bars is just double ? same for 120 bmp just divide by 2 ?

does anyone know if it works like this for pitching samples ? because a sample plays exactly double when it is pitched 1 octave up . so the length of the sample ends up exactly half

[kel]

Tempo and Pitch-Shifting Calculator:
http://www.thewhippinpost.co.uk/tools/t ... ulator.htm
midway down

[ghost ghost ghost]

Yo thanks to everyone who has posted in this thread. Big help.

dope resource, kel, bookmarked.

60 divided by BPM = how many seconds 1 beat takes.

so say

75BPM

60 divided by 75 = 0.8

so 1 beat at 75BPM is 0.8seconds.

for 1 bar just multiply 4 by 0.8 or whatever the result of the first equation is... for more than 1 bar.. well pretty obvious

Ok I think I've definitely got it down now. So I divide 60 by the bpm to find the length of one beat, then multiply that figure by 4....so one bar at 75bmp would be 3.2 seconds. Would that be right?

This is something I've literally lost sleep over so once again thank you all.

[cartesia]

1 beat @ 75BPM = 0.8seconds

so...

4 beats @ 75BPM = 0.8 times 4

= 3.2seconds

yep, you got it!